Combined pneumatic and hydraulic resilient suspension and shock absorbing device for vehicles



A. H. WEIERTZ ETAL- AND SHOCK ABSORBING DEVICE FOR VEHICLES COMBINED PNEUMATIC AND HYDRAULIC RESILIENT SUSPENSION FIL-'n.5

July 7, 1953 Filed March 7, 1951 July 7, 1953 A. H. WEIERTZ ETAL 2,644,699

COMBINED PNEUMATIC AND HYDRAULIC RESILIENT SUSPENSION AND sEocx ABsoRBING DEVICE EoR VEHICLES 2 Sheets-Sheet 2 Filed March 7, 1951 FME-n.5

Patented July 7, 19753 COMBINED lPNEUMA'rIC 'AND HYDRAULIC REslLIENT SUSPENSION AND SHOCK AB- SORBING DEVICE FOR .VEHICLES 1 l Axel Huge Weiertz; Malmo, and stig Herbert Albert Weiertz, Svedala; Sweden Y Application Maren 7, 1951, serial Ne."214,312 'Y In SWedcrlMarch 8, 1950 13 Claims. (Clean-124) i This invention relates to a combined pneumatic and hydraulic resilient suspension and shock absorbing `device for vehicles, particularly motor vehicles and especially automobiles and crosscountry Vehicles.

An object of the invention is to provide a resilient suspension and shock absorbing device of the'above type, the function of which" is tov automatically adjust itself in an advantageous manner to the nature of the road surface as well as to the load of the vehicle.

'Another object of the invention is to provide a device of the above type and of such a char-vv acter that the height of the vehicle above the roadsurface will normally be independent of the vehicle load and instead adjust itself to the nature of the road surface.

Still another object is to providea device of the above type which will automatically adapt its lfunction .to the travel of the vehicle through' curves, thus counteracting lurching Of the vehicle.

A still further object is to provide such a device which will fully eliminate the need of metal body suspension springs.

Further objects and features of the invention will become apparent in the course of the following description, reference kbeing had to the accompanying drawings which illustrate two preferred embodiments of the invention. In the drawings:

Fig. 1 is a side view, partly in section, of a sedan type carv incorporating one embodiment Vof the combined pneumatic and hydraulic resilient suspension and shock absorbing device according to the invention; l *Y Fig. 2 isa plan View of the same embodiment;

In this embodiment the resilient suspension and shock absorbing device comprises four units each associated with one of the four road Wheels of the car.

Fig. 3 is an axial section on a larger scale through such a unit;

. Fig. 4 is a section on a still larger'scale through certain details of the same unit; Y f

Fig. 5 in the same manner as Fig. 1 shows a car incorporating a somewhat modied embodiment of the combined pneumatic and hydraulic resilient suspension and shock absorbing device accordingto the invention; 'o

Fig. 6 is aplan view corresponding to Fig. 5 of the front end portion of the car; N

Fig. 7 Vis a section on a larger scale through one of the units ofthe device, which are associated each with one of the road Wheels ci the'vehicle'.v

Referring to Figs. `1 therein is built for front steering and rear drive and has its motor l disposedrbehind the rear seat and infrontof the rear wheels of the car. The chassis andthe body are made in a so-called shell structure having la great torsion rigidity Vabout its longitudinal axis. The center of gravity is located farther to the rear than would be the caserif the motor were disposed in the front end portion of thev car. The motor and power transmissionare available Athroughrbig side openings;l

and through vthe luggage behind said openings. I v

The combined pneumatic and hydraulic resilient suspension and vshock absorbing device comprises four unitsfalssociated: each `with one of the four road wheels of the car and "operating between the chassis andv the respective wheels, the chassis being suspended by said units from joints 2, 3v supported by the road Wheels. At least when the'car is driven at normal speed, the center of gravity of `the chassis is located substantially lower than the suspension jointsvv 3. Each unitv comprises 'aj' hydraulic cylinder 4 secured to the chassiswand a'piston 5 movable therein andconnected by means of a piston rod 6 with an arm 1. Said armis mounted for vertical swinging movement in relation to the chassis by having its front end pivoted thereto by means of a pivot 8. The rear ends of the arms are atcompartment. situated tached to the respective suspension joints 2 and' 3. Each of these joints may be a ball and socket joint or comprise' a pivot mounted yin a'. rubber bearing, sonthat the frequired movability is obtainedrin" the suspension joint.'I At each of the steering Wheels 9 the joint 2 is arranged atfthe.

top end of the wheel steering knuckle l0, about which the wheel is swingable for steering purposes by means of the 'steering gear. For its parallel 'motion in relation to the chassis the steering knuckle Hl is connected at its lower end with the rear end of an arm Il which, like arm l,A `has its front end pivoted to the chassis. At each rear wheel l2 the joint'3 is disposed on a support yI3 arranged onthe wheel'axle bearing, preferably on the brake shield of the'wheel. For parallel motion of thegtwolrear wheels their axle bearingsare connected" on the one hand withvthe chassis by means.of"forwardlyfdirected arms I4 andlinks l 5 and on the other hand with one another by means Of aj'tierod `52'rnovably secured to the wheel axle bearings by means of yokes and verticaly pivots'53. i Y y At its upper end the cylinder 4 is provided With a'cover or head'l (Figs. Sand '4) in'which there and 2, the car shown in communication through a number of ports 2| of a limited size. Some, butnot all, of said ports are provided with check valves 22 permitting a ow of iluid to pass from the cylinder4 into the chamber I1 but not lin the reverse direction. The chamber I1 is connected with an oil circulation system comprising a pump 23 (Fig. 2) driven by the motor I and having a suction conduit-24 from which branches lead to the resilient suspension and shock absorbing units at all four road wheels, said pressure conduit 26 being connected in each of these units with the chamber I1 which,

in addition, is connected with a conduit 21y for returning the oil to the sump 25. Likewise con-- nected with the return conduit 21 is the space below the piston in the cylinder 4, said space being sealed downwards by means of a bellows 28 and provided with a venting tube 42 which is open at its top. Y

The communication of the chamber I1 with the pressure conduit 26 from the vpump V23 is con-V trolled by a valve 29 disposed in a valve-housing 38 whichis integral with the cylinder head IE, Valve 29 is in the form of a piston obliquely cut at-its top, said piston being movable in a bore in the valve housing 30 and so controlling diamet5 rically opposed ports to the pressure conduit 26 and the chamber I1, which ports open into the bore, that the valve piston 29v when moving upwardly to close the said ports', begins and concludes the closing of the port to the chamber I1 before it begins and concludes, respectively, the closing ofthe port vto the pressure conduit 26. The valve 29 is operatively'connected .with the arm-1 so that-upon movement of. thepiston 5 upwardly or downwardly in the cylinder. 4 the valve 29 is displaced downwardly or upwardly, i.e. in its opening or closingdirection, respectively. The connection between valve 29 and arm 1 may consist, for instance as shown in Fig. 3, of a tie rod 3| with a toggle joint 32, so that the effective length of the tie rod is adjustable bya member 33 engaging at the toggle joint 32 and operable manually or otherwise. As shown in Fig. 4, the chamber I1 is connected with the return conduit 21 byv means of a calibrated throttle opening 34 and a checkl valve 35 which may bel forced fromv its seat in the Yvalve housing 30 by a member 36 operable manuallyY or otherwise. The connection of the check valve and preferably also of the throttle opening 34 to the conduit 21 .extends through the space below the valve piston 29 which is suitably urged in its closing direction by a spring 31. In the lower portion of the chamber I1 a cup 38 may be disposed, provided on its underside with vdistance members and having suitably .distributed and shaped through-flow openings 39 for the oil, said open.- ings being offset in relation to the ports 2l. .Said cup 38 serves the purpose of better distributing the oil pressure from the cylinderA on the bladder I8 and of preventing the latter, when expanded from penetrating or possibly `being clamped or damaged in some of the openings in the wall of the chamber I1. A spring 40 isadapted for asoft limitation of the downward move- "4 ment of the piston 5 in the cylinder 4, and mounted on the chassis is a stop 5I e. g. of rubber, with which the arm 1 cooperates to limit the upward movement of the piston 5 in the cylinder 4. A

pressure relief valve (not shown) may be arranged for limiting the 1voil-,pressure generated by the pump 23 in thepressure conduit 'V26 to a certain maximum value.

The function of the device is as follows. As soon as the motor I is started, the pump 23 will operate'and thus presses oil through the pressure conduit. 2,6; into thev chamber I1 and the space above `the piston 5 in the cylinder 4 of each@ of the units associated with the road wheels. The pressure oil urges the piston 5V downwards Ain the cylinder 4 and may compress coming from a sump 25 and a pressure conduit 26 the air bladder I'B'more or less in dependence on the initial' pressure therein and on the vehicle load, until the valve 29 throttles the connection between the chamber I1; and the pressure conduit2fsuillciently ini-order that the flow of oil into the chamber I1 ..and..th e discharge of oil from said chamber. through .thel throttlev opening 34 (and the pcvassibley leakage past the piston 5 in the cylinder 4) may keep in step with one another. A t this, thechassisA will have been raised in relation'tdthe road. wheels up toa level above ground Awhich is independent ofY the" vehicle load. The pressure .building up inthe chamber I1and the air-lledbladder IBwill vary with the vehi-t cle load land the natureyof Ythe 'road'surfaca and as a desirable result thereof the resiliency 'which' is dependent ontli-amountpf ail-'enclosed within the compressible'bladder".18, wilLbecornetheY softer, the less-loadedtheyehcle is and the more rugged the road"sur'fa'cefis, as. will be'explained in detail in the following.l Qn propulsion of the car the deviceacts'not lonly as a Vvehicle spring whose stillness Iincreases.'with'.the vehicle load,butsimultaneously asa hydraulic shock absorber becausey of ft ecnnectionports 2I between the 'chamber' I'Tahd thespace above th-e piston 5 i n th ecylinder .4. being relatively narrow' and scmcfjthemcbei g1i.provided"with check valves'V 22. The shock'labsorptio'ri isfimprov'ed by the -valve 29- temporarily increasing 'the supply of oil under pressur'eto the'lchamber, I1 at" each occurring shock and'fth. -more so,l the more vigorous thef'shoc'k is., f"Th`1stemporary increase in the supply of pressure' oil .occurs suddenly at 'the shock as a result of Ithe piston 2,9,` by its downwardly directed. .opening movement, accelerating the oil Ysupply to fthe space vabove the piston 29 and 4immediately afterwards causing said space to communicate with the opening in 'the valve housing 30, leading therefromto the chamber I1.A .Since the oil supply 'to :the chamber I1 is thu-s temporarily increased at leach shock and the. more so, the more vigorous this shock is,

the oil amount 'in the Achamber I1 and the space "above the piston 5 in the cylinder 4 and consequently also the heightof the vehicle above ground becomes greater, vthe Vmore 'rugged the road surfaceis. Atthe same'ti'rne the'resiliency becomes softer as a result ofthe ratio, varying with the height of the vehicle above ground, between the momentv armsof the 'forces acting upon the arm` 1,v and the resultingsmaller pressurevonthepiston E'and the bladder I8. Furthermore, the device can be manually' or other- Y wise adjusted to. thatevel above ground, on which itwillholdfth'e, chassis, ,by the ladjusting member 33, i.. e. by. changing the relative positionsof the control valve. `29V and the piston .5 in thev cylinder 4,V Withthe useof the adjusting means 33 the' device-may' also' be utinzed as -al hydraulic jack for elevating the chassis, elg. for' permitting changing of tires. After elevation of the chassis by supply of pressure oil to the chamber l l, the chassis may be supported in the elevated position by means of an unfoldable'support 4I (Fig. l), whereupon oil can be' discharged from the chamber il e. g. by opening of the valve 35,the wheel being automatically raised by the spring 40 (Fig. 3) which hasv been compressed at the supply of oil and the elevation of thechassis.

Referring now to Figs. 5 to 7, the embodiment shown therein differs from the first embodiment substantially in the followingrespects. The -car has its motor l. located in vthe front end 4portion of the-chassis and is assumed built forfront drive'and front steering. The hydraulic cylin-l` ders d containing the pistons 5 engaging the 4arms 'l with their piston rods 6, are mounted ina rearwardly inclined position on the chassis. Mounted at the front end portion of the chassis is a pendulum d3 having an extension 44 projecting upon the members s6. On driving through a curve the pendulum i3 makes a deflection under the influence of gravity and acts through the pulling means l5 and the tie rodsd, 49 on the control of the valves 29, 35 in relatively opposed directions at the units on the two opposedl sides of the vehicle, so that the tendency of the latter of lurching under the influence of gravity is counteracted by the fact that a suitable difference arises betweenA the oil pressures and oil amounts, resulting from the control of the valves 29 and 35, in the units on the two opposedsides of the vehicle. Y I

The compressible air container or bladder I8 in the chamber il has a two fold task, Viz. to prevent air from being mixed with the o il and to render possible the imprisonment and maintaining of a larger air volume at a correspondingly greater pressure within the limited space in the chamber il also when the oil pressure therein sinks. This is desirable'in View of the fact that the resiliency is dependent on the amount of air which is imprisoned in the chamber H and which has `to be suiiciently large in order that the shockv absorber may simultaneously iulll the task of a vehicle spring.

Many modifications oi the described device arel conceivable within the spirit of the invention. The invention must not therefore be considered limited toV the embodiments which have been described above and shown in the drawings to elucidate the invention.

What We claim and desire to secure by Letters Patent is:v

1. In a wheeled motor vehicle having supports for supporting thebody of the vehicle from the wheels thereof, a combined pneumatic and hydraulic resilient suspension and shock absorbing device comprising a circulation system for a liquid fluid mounted.v on the vehicle, a pressure-- generating pump driven fromithe motor f the vehicle and connected in said circulation system Theipulling means d are held stretched by springs 50 which actl for circulating the liquidfluid therein, a .shock absorber acting between the vehicle body and any `of the supports therefor and comprising a hydraulic cylinder and a piston movable there.- in, a chamber associated with said hydraulic cylinder and connected in said liquid iiuid circulation system, a` wall forming part oflslaid f y chamber and havingrestricted ports providing lccrnrriunica'tion betweensaid' chamber and the space )on one side of said piston in said cylinder, and'means for imprisoning in said chamberin separated relation to the liquid iiuid andnever-V theless subjected to the pressure thereof, a vsuiicient amountof a lgaseous fluid for causing the shock absorber to fulfill also the task of a vehicle Spjrins. r 1

25, In a wheeled motor Vehicle a combined pneumatic i and hydraulic resilient suspension and shock absorbing device as claimed in claim 1, in which said means comprises a substantially spherical biadder and in which said chamber is spherical in order that it may be completely lled by, and thus practicallyeverywhere sup-r port said bladder imprisi'oning the gaseous fluid in said chamber,y

3. v,In a r,wheeled motor. vehicle having separate supports for supporting the body of the vehicle from the separate wheels, the combination of a circulation system for a liquidiiuid and a pressure-generating pump driven from Athe motor of the vehicle and connected in saidr circulation' system for circulating'the liquid fiuid therein, with a separate combined pneumatic and hyy draulic resilient suspension'and shock absorbing device .between` each of the separate supports iorthe vehicle body and the latter, said device comprisinga lever mounted for vertically swinging movement 'on thevehicle body and connected to thev respective support, a hydraulic cylinder secured jto the' vehicle body, 'a cylinder head at one end'oflsaidcylinder, a piston movable in said cylinder, jai piston rod projecting fromA said f piston through the otherend of said cylinder and connected to said lever, said cylinder head forming a chamber connected in 'said liquid iiuid l.circulation system and )communicating through restricted ports in its wall with the adjacent end of said cylinder, and means in said chamber for imprisoning 'therein an essential amountof a e'aeous fluid in separated relation to the liquid.

fluid'and nevertheless subjected to the pressure thereof.

4.' The combination claimed in `claim 3, and

check valves in some of vsaid restricted ports allowingl ow ofpressure uid from said cylinder into said chamber but not in the reverse direction.

' 5'. The combination claimed in claim 3, and

a control valve connecting said chamber with the pressure side or said pump in said circulation system and operatively connected with said from the separate wheels thereof, fthe combina-- tion comprising a pressure-generating'pump forv a' liquid fluid driven 'from the motor ofv thevehicl'e, a combined pneumatic and hydraulic resilv ient suspension and shock absorbing device acting between thevehicle body and said supports and comprising for each of said supports a lever mounted at one end vforl vertically swinging movement on the vehicle body and articulatedat its other end -to the support, and a shock absorber comprising a hydraulic cylinder secured to the vehicle body, a piston movable in said cylinder, means projecting through one end of said cylinder and connecting said piston to said lever at a point between the ends thereof, and a cylinder head on said cylinder at the other end thereof, said cylinder head forming a chamber= communicating through restricted ports in Y its wall with the adjacent end of said cylinder,

a conduit for liquid pressure uid from the pressure side. ofI said pump, a control valve between said chamber and said pressure conduit, a return conduit for the liquid fluid from said chamber to said pump, means for controlling the escape of liquid pressure fluid from said chamber to said return conduit, and means in said chamber for .imprisoning therein an essential amount of -a gaseous uid in separated'relation to the liquid pressure fluid and nevertheless subjected to the pressure thereof.

7. The combination as claimed in claim 6, in which the control valve between said chamberv to said liquid pressure fluid is operatively connected with the movable piston in the hydraulic cylinder of the shock absorber in such a manner that said control valve is moved in its opening direction when said piston is moving towards the cylinder head.

V8. A combined pneumatic and hydraulic resilient suspension and shock absorbing device of the .characterdescribed comprising a hydraulic shockabsorber comprising a hydraulic cylinder, a piston movable in said cylinder, and a cylinder head at one end of said cylinder, said cylinder head forming a chamber communicating through restricted ports in its wall with the adjacent end of said cylinder, said chamber having an inlet for liquid pressure fluid and an outlet for the escape of such uid, means for controlling said inlet and outlet Vin dependence on the movements of .said piston in said cylinder,

Y means in said chamber for imprisoning therein a substantial amount of gaseous fluid in separated relation to the liquid pressure fluid and nevertheless? subjected to the pressure thereof, and means for venting and draining the cylinder at the end thereof removed from said cylinder o head.

9. In a wheeled motor vehicle with a combined pneumatic and hydraulic resilient suspension and shock absorbing device as claimedin claim 8 for supporting the body of the vehicle from each of the wheels, the combination with` mentioned means in dependence on the move-` ments of the pendulum as to cause said devices to counteract lurching of the vehicle when travelling through curves.

l0. In a wheeled motor vehicle having separate supports for supporting the body of the vehicle from the separate wheels thereof, the combination comprising a pressure-generating pump fora liquid vfluid ydriven from the motor of the vehicle, a combined pneumatic and hydraulic resilient suspension and shock absorbing device acting between the vehicle body and said supports and comprising for each of said supports a lever'mounted at oneend for vertically swinging movement on the vehicle bodyand articulated at its `other end to the support, and a shock absorber4 comprising a hydraulic cylinderl secured to the vehicle body, a piston 'movable-in said cylinder, -means proj ectingmthrough. one end of said cylinder andconnecting said piston to said lever at a point between the ends thereof, and a cylinder head on said 'cylinder at the other end thereof', said cylinder head forming a chamber communicatingY through restricted ports in its Wall with the adjacent end of said cylinder, a conduit for liquid pressure fluid from the pres,- sure side of said pump,fa control valve between said chamber and said pressure conduit, a return conduit for the liquid fluid from said chamber to said pump, a calibrated throttle for controlling the escape of liquid pressure uid from Y said chamber to said return conduit, and means mounted at one end for vertically swinging movement on the vehicle body and articulated at itsl other end to the support, and a shock absorber comprisinga hydraulic cylinder secured to the vehicle body, a piston movable in said cylinder, means projecting through one end of said cylinder and connectingsaid'piston to said lever at a point between the ends thereof, and a cylinder head on said Ycylinder at the other end thereof, said cylinder-head vforming a chamber communicating through restricted ports in its wall with the adjacent end of said cylinder, a conduit for liquid pressure fluid from the pressure side of said jump, a control valve between said chamber and said-pressure conduit, a return conduitfor the liquid fluid from said chamber to said pump, means for controlling the escape of liquid pressure fluid from said chamber to said return conduit, means in said chamber for imprisoning therein an essential amount of a gaseous uid in separated relation to the liquid pressure fluid ,and nevertheless subjected to the pressure thereof, and links connecting said control valve to said lever lfor moving said control valve in itsy opening direction on movement of said piston in said cylinder towards the cylinderl head. and an adjustable member connectedV to said control valve and said piston.

l2. In a wheeled motor vehicle having separate supports for-supportingV thebody of the vehicle from the separate wheels thereof, the combination comprising a pressure-generating pump for a liquid uid driven from the motor of the vehicle, combined pneumatic and hydraulic resilient suspension and shock. absorbing device acting between the vehicle body and said supports and comprisingy for each of said supports a lever mounted at one endfor vertically swinging movement on the vehicle bodyand articulated at its other end to the support, anda shock absorber comprising a hydraulic cylinder secured to the vehicle body, a piston movable in said cylinder, means projecting through one end of said cylinder and connecting said piston to said lever thereof, said cylinder head forming a chamber communicating through restricted ports in its wall with the adjacent end of said cylinder, a conduit for liquid pressure fluid from the pressure side of said pump, a control valve between said chamber and said pressure conduit, a return conduit for the liquid iluid from said chamber to said pump, means for controlling the escape of liquid pressure fluid from said chamber to said return conduit, means in said chamber for imprisoning therein an essential amount of a gaseous fluid in separated relation to the liquid pressure fluid and nevertheless subjected to the pressure thereof, said means for controlling the escape of liquid pressure fluid from said chamber comprising a valve and means operating in dependence on the movements of said piston in said cylinder for controlling said valve.

13. A combined pneumatic and hydraulic resilient suspension and shock absorbing device of the character described, comprising a hydraulic shock absorber comprising a hydraulic cylinder, a piston movable in said cylinder, and a cylinder -head at one end of said cylinder, said cylinder head forming a spherical chamber'communieating through restricted ports in its Wall with the adjacent end of said cylinder, said chamber having an inlet for liquid pressure fluid and an 10 outlet for the escape of such fluid, means for controlling said inlet and outlet independence on the movements of said piston in said cylinder,

a. spherical bladder With an inilating valve projecting through the Wall of the chamber at the top thereof for imprisoning therein a sub-l stantial amount of a gaseous uid in separated i.

relation to the liquid pressure uid and nevertheless subjected to the pressure thereof, and means for venting and draining the cylinder at the end thereof remote from said cylinder head, a cup-shaped member in said chamber on the bottom thereof, said member having openings References Cited in the file ofvthis patent UNITED STATES PATENTS Number Name Date 2,196,089 Wallace Apr. 2, 1940 2,490,311 Du Rostu Dec. 6, 1949 2,521,074 Marston Sept. 5, 1950 

